1. Field of the Invention
The present invention relates generally to hole saws and more specifically to a hole saw having efficient slug removal that allows a slug to be removed from the hole saw without the use of tools.
2. Discussion of the Prior Art
The most common type of hole saw is a cup with teeth formed on the open end, a shank attached to the other end of the cup, and a drill retained in the shank. The drill starts the hole cutting process by providing a pivotal anchor for cutting the hole with the cup. However, an aggravating problem encountered with hole saws is the removal of the slug from the cup. Depending upon the material of the slug, removal of the slug can be a major challenge. If the material is plastic, the plastic slug will heat bond to the inside surface of the cup. There are numerous solutions proposed for removal of the slug. The simplest method of slug removal is to form openings in the top and/or side of the hole saw to allow the slug to be pushed or pried out with a tool.
U.S. Pat. No. 4,652,185 to Malrick discloses hole saws. A spring loaded washer is used to push the slug out of the hole saw. However, if the material is plastic, hand pressure may not be sufficient to push the plastic slug out of the hole saw. U.S. Pat. No. 5,435,672 to Hall et. al discloses a hole saw having plug ejection feature. The hole saw having plug ejection feature includes a screw arbor, which is rotated to eject a slug therefrom. However, this design of hole saw is more complicated than the most common hole saw and requires the screw arbor to be rotated to remove the slug. U.S. Pat. No. 6,206,616 to Smith et al. discloses a tool and method for cutting a circular opening and retaining the cut portion.
Accordingly, there is a clearly felt need in the art for a hole saw having efficient slug removal that includes at least two modified teeth that reduces the size of the slug and a relieved drill that allows the reduced slug to fall out of the hole saw.
The present invention provides a hole saw having efficient slug removal that allows a slug to removed therefrom without a tool. The hole saw having efficient slug removal includes a saw cup, a shank portion, and a location drill. A plurality of cutting teeth are formed on an open end of the saw cup and the shank portion is attached to the other end of the saw cup with any suitable fastening process. An opening is formed through the shank to receive the location drill. Preferably, a set screw or the like is used to retain the location drill in the shank portion. The saw cup is modified such that at least two cutting teeth protrude inward. The at least two inward cutting teeth may be two existing cutting teeth bent inward, or at least two inward cutting teeth attached to an inside surface of the saw cup. The at least two inward cutting teeth are preferably located substantially equidistant from each other about the circumference of the open end. The at least two inward cutting teeth create a slug which will fall out of the saw cup.
The location drill is modified such that a cutting diameter has a short length and the remainder of the length is relieved, such that the remainder of the length is smaller in diameter than the cutting diameter. When the hole saw is turned such that the open end is facing downward, the slug drops until it contacts a bottom cutting diameter edge of the location drill. The slug may be removed from the drill by hand. A compression spring may be added to the hole saw to eject the slug when the open end of the saw cup is facing upward. A bottom of the compression spring is attached to a top of the saw cup, on an inside surface of the top.
Accordingly, it is an object of the present invention to provide a hole saw having efficient slug removal that reduces the size of the slug.
It is a further object of the present invention to provide a hole saw having efficient slug removal that includes a relieved drill that allows the reduced slug to fall out of the hole saw.
Finally, it is another object of the present invention to provide a hole saw having efficient slug removal that includes a compression spring that ejects a slug when the open end of the saw cup is facing upward.
These and additional objects, advantages, features and benefits of the present invention will become apparent from the following specification.